The powered handpiece has evolved into an important tool for performing surgical procedures. A typical powered handpiece includes a housing that contains an electrically driven motor. A coupling assembly is attached to one end of the handpiece. The coupling assembly is used to releasably secure a cutting accessory to the motor so that the motor, when energized, actuates the cutting attachment. The development of powered surgical handpieces and their complementary cutting accessories has made it possible to cut, shape and remove both hard and soft body tissue at faster rates and with a higher degree of accuracy than was possible with the manually powered tools that preceded them.
When a cutting attachment is actuated, the cutting action causes loose tissue and other debris to develop at the surgical site. This material is removed by applying an irrigation fluid to the site and also drawing a suction from the site. The irrigation fluid serves as a transport media for carrying the debris; the suction draws away the fluid and the entrained debris. In order to perform this irrigation and suction, some cutting attachments are provided with conduits through which fluid is applied to and drawn from the surgical site. For example, cutting attachments designed to perform endoscopic surgery or sinus surgery often include a static outer sleeve in which a rotating tube is fitted. The head of the rotating tube is provided with some type of cutting surface or cutting member. Each of these attachments is further shaped so that irrigation fluid can flow to the surgical site through the annular channel between the rotating tube and the static sleeve. The inner rotating tube is further provided with an opening adjacent the head through which a suction is drawn from the surgical site. Thus, the inner tube serves as the conduit through which the irrigation fluid and debris are removed from the surgical site.
A powered handpiece intended for use with the above cutting attachments is designed with complementary features that facilitate the drawing of the suction away from the surgical site. Specifically, this type of handpiece is provided with a suction bore to which a suction pump is applied. The coupling assembly allows fluid flow from the inside of the rotating tube to the suction bore. Moreover, the handpiece is provided with a valve for regulating fluid flow through the suction valve. Thus, a surgeon using this type of handpiece can, with one hand, both manipulate the cutting accessory and regulate the rate at which fluid is drawn from the surgical site.
While current handpieces have provided useful for both driving cutting attachments and drawing a suction, there are some disadvantages associated with their use. In particular, current handpieces and their complementary cutting attachments are designed so that irrigation fluid is introduced into the annular channel through a supply line that is separate from the handpiece. While this supply line may be attached to a handpiece, it has a free end that is typically located forward of the handpiece coupling assembly. The free end of this line has to be manually fitted to an inlet luer integral with the static sleeve. When, during a surgical procedure, the doctor wants to switch cutting attachments, this line must first be removed from the cutting attachment being separated from the handpiece. Then, after the new cutting attachment is installed, the supply line must be manually fitted to the new attachment. The time it takes to perform these steps adds to the overall time it takes to perform the surgical procedure.
Moreover, in these surgical handpieces, the motor is in close physical proximity to the path through which the suction fluid flows through the handpiece. Accordingly, these handpieces must be constructed to include sufficient seals that prevent liquid flow into the components forming the motor. However, over time, and owing to the presence of the moving parts against which these seals press, these seals can wear out. Consequently, it is not uncommon for fluid to enter the motor and cause the components forming the motor to corrode and/or malfunction. Once the integrity of these seals diminishes, this corrosion and motor component wear can occur at a relatively fast rate because the fluid drawn through the handpiece suction is saline.
Also, occasionally, debris can clog the cutting accessory rotating tube through which the suction is drawn from the surgical site. This clogging is especially prone to occur in cutting accessories designed for performing sinus surgery. This is because the diameter of the bore through which this suction flow travels is relatively narrow. Presently, there are two ways a surgeon can try to remove this type of clog in order to reestablish suction at the surgical site. One method involves introducing a large quantity of irrigation fluid into the surgical site. The surgeon takes this action by momentarily running the irrigation pump used to supply fluid at a high speed/high flow flush setting. The introduction of this large quantity of water causes a large fluid pressure head to develop in the rotating tube upstream of the clog. If the conditions are right, the pressure head of this fluid forces the clog-causing debris to flow downstream out of the rotating tube. One problem with this clog removal technique is that the switches for regulating the irrigation pump are typically located off the handpiece. In order for the surgeon to be able to control the pump, he/she must actuate a separate foot or hand switch or instruct an assistant to perform this operation. In each of these situations, the surgeon may have to significantly divert his/her attention from the actual surgical procedure being performed. Still another problem with this method of clog removal is that, often, it simply does not work. Then, the surgeon is left with a situation in which excess fluid has been introduced into the patient.
The second method of clog removal is more mechanical. This method involves running a rigid wire down the rotating tube in order to force the clog out of the tube. When a surgeon has to take this action, he/she must first withdraw the cutting attachment from the surgical site. Then, once the clog is removed, the cutting attachment must be repositioned so that the surgical procedure can be completed. The need to perform these tasks adds to the overall time it takes to perform the surgical procedure.